Brake, Cruise lights on Blinking- SOLVED, but Is this even possible?

I've owned a 2010 Subaru Legacy for about 2.5 years, and about a year in,
the CEL came on and the Brake and Cruise lights started blinking.  Checked
the codes, said O2 Sensor.  OK, there's 240k on the odo, things happen.  
Thought about getting it replaced, then the light goes out for a few days.  
Rinse and repeat for the next year, the same thing keeps happening off and
on, then the codes come on and stay on.  Part 2:

Fast forward to 263,000 miles.  Codes are present 90% of the time.  RR
Wheel hub assembly replaced, then about a month later, steering and
brakes are total garbage coming off the interstate.  I limp home, tear the front
wheels off to dismantle/inspect the brakes and see a rip in the front
subframe/engine cradle.  I call the shop, they quote the job over the phone
and tell me to round up the parts (harder than it sounds!).  The car is towed
to the shop for the subframe swap.  4 days later, I go to pick up the car and
the shop owner shows me the rotted subframe; One ball joint was completely
disconnected, and the whole top side of the frame is cancerous, and it wasn't
visible from the underside, so I missed it completely.  

Part 3: Here's where it gets weird.  I drive the repaired car home, thankful
that I didn't have the subframe come apart on the interstate.  The next day I
head out to drive to the store and realize there are NO CEL/brake/cruise
lights on.  A week later, still no codes.  Took a 500-mile trip - No codes.  I'm
more than a month post-repair and still haven't seen a single reoccurrence of
the code issue to date.  

Is this possible?  No other work was performed.  Was the engine out of
position due to the declining subframe and was popping codes as a result?  
The CEL/brake/cruise light anomaly bedevils many 5th-Gen Subie owners,
but I would have thought the fix would be something that was actually
connected to the computer.  

I wanted to post this because this issue/fix combination isn't posted online
anywhere, and if one person gets a subframe inspection instead of ending
up in a ditch, it was worth it.

Cost to repair wasn't cheap, but cheaper than buying another car: Parts were
about $750 for the OEM subframe, lower control arms and sway bar ends;
Labor (including alignment) was another $725.  Local independent shop did
the work, dealer cost to do the job would be likely be much higher.

IS this even possible?  The computer is working perfectly.